1. Field of the Invention
The present invention is generally in the field of electrical circuits. More particularly, the invention is in the field of oscillators and mixers.
2. Background Art
Wireless communications devices, such as cell phones, wireless LANs, and satellite set top boxes, typically utilize a “local oscillation generator” (also referred to simply as a “local oscillation generator” in the present application) to provide different frequencies as required for operation on desired communication channels. For example, the local oscillation generator can provide an output signal having a reference frequency to respective transmitter and receiver sections of a wireless communication device for upconversion and downconversion of an input frequency. The local oscillation generator can generate an output signal having a desired reference frequency by combining a signal having a primary frequency with a signal having an appropriately divided frequency in a mixing stage of the local oscillation generator.
In a conventional local oscillation generator, a signal having a divided frequency can be generated and provided to the mixing stage by utilizing switches to selectively route the primary frequency signal through one or more frequency dividers. Thus, typically in the conventional local oscillation generator, the path of the signal having the divided frequency passes through one or more such switches. However, parasitic capacitor and resistance in typical switches can undesirably cause signal loss, which is particularly undesirable for local oscillation generators used in mobile wireless communication devices, such as cell phones.